diff --git a/grass_internal/src/ast/expr.rs b/grass_internal/src/ast/expr.rs
index e73d3cb..725fc96 100644
--- a/grass_internal/src/ast/expr.rs
+++ b/grass_internal/src/ast/expr.rs
@@ -1,4 +1,4 @@
-use std::iter::Iterator;
+use std::{iter::Iterator, sync::Arc};
 
 use codemap::{Span, Spanned};
 
@@ -43,9 +43,9 @@ pub(crate) struct AstSassMap(pub Vec<(Spanned<AstExpr>, AstExpr)>);
 #[derive(Debug, Clone)]
 pub(crate) enum AstExpr {
     BinaryOp {
-        lhs: Box<Self>,
+        lhs: Arc<Self>,
         op: BinaryOp,
-        rhs: Box<Self>,
+        rhs: Arc<Self>,
         allows_slash: bool,
         span: Span,
     },
@@ -55,9 +55,9 @@ pub(crate) enum AstExpr {
         name: CalculationName,
         args: Vec<Self>,
     },
-    Color(Box<Color>),
+    Color(Arc<Color>),
     FunctionCall(FunctionCallExpr),
-    If(Box<Ternary>),
+    If(Arc<Ternary>),
     InterpolatedFunction(InterpolatedFunction),
     List(ListExpr),
     Map(AstSassMap),
@@ -66,11 +66,11 @@ pub(crate) enum AstExpr {
         n: Number,
         unit: Unit,
     },
-    Paren(Box<Self>),
+    Paren(Arc<Self>),
     ParentSelector,
     String(StringExpr, Span),
-    Supports(Box<AstSupportsCondition>),
-    UnaryOp(UnaryOp, Box<Self>, Span),
+    Supports(Arc<AstSupportsCondition>),
+    UnaryOp(UnaryOp, Arc<Self>, Span),
     Variable {
         name: Spanned<Identifier>,
         namespace: Option<Spanned<Identifier>>,
@@ -174,9 +174,9 @@ impl AstExpr {
 
     pub fn slash(left: Self, right: Self, span: Span) -> Self {
         Self::BinaryOp {
-            lhs: Box::new(left),
+            lhs: Arc::new(left),
             op: BinaryOp::Div,
-            rhs: Box::new(right),
+            rhs: Arc::new(right),
             allows_slash: true,
             span,
         }
diff --git a/grass_internal/src/builtin/functions/color/hsl.rs b/grass_internal/src/builtin/functions/color/hsl.rs
index 9920c3d..b6901b7 100644
--- a/grass_internal/src/builtin/functions/color/hsl.rs
+++ b/grass_internal/src/builtin/functions/color/hsl.rs
@@ -59,7 +59,7 @@ fn hsl_3_args(
         visitor,
     )?;
 
-    Ok(Value::Color(Box::new(Color::from_hsla_fn(
+    Ok(Value::Color(Arc::new(Color::from_hsla_fn(
         Number(hue.num.rem_euclid(360.0)),
         saturation.num / Number(100.0),
         lightness.num / Number(100.0),
@@ -172,7 +172,7 @@ pub(crate) fn adjust_hue(mut args: ArgumentResult, visitor: &mut Visitor) -> Sas
         .assert_number_with_name("degrees", args.span())?
         .num;
 
-    Ok(Value::Color(Box::new(color.adjust_hue(degrees))))
+    Ok(Value::Color(Arc::new(color.adjust_hue(degrees))))
 }
 
 fn lighten(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -186,7 +186,7 @@ fn lighten(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value>
         .assert_number_with_name("amount", args.span())?;
     let amount = bound!(args, "amount", amount.num, amount.unit, 0, 100) / Number(100.0);
 
-    Ok(Value::Color(Box::new(color.lighten(amount))))
+    Ok(Value::Color(Arc::new(color.lighten(amount))))
 }
 
 fn darken(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -213,7 +213,7 @@ fn darken(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value>
                 .into())
         }
     };
-    Ok(Value::Color(Box::new(color.darken(amount))))
+    Ok(Value::Color(Arc::new(color.darken(amount))))
 }
 
 fn saturate(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -271,7 +271,7 @@ fn saturate(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value
                 .into())
         }
     };
-    Ok(Value::Color(Box::new(color.saturate(amount))))
+    Ok(Value::Color(Arc::new(color.saturate(amount))))
 }
 
 fn desaturate(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -297,7 +297,7 @@ fn desaturate(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Val
                 .into())
         }
     };
-    Ok(Value::Color(Box::new(color.desaturate(amount))))
+    Ok(Value::Color(Arc::new(color.desaturate(amount))))
 }
 
 pub(crate) fn grayscale(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -322,7 +322,7 @@ pub(crate) fn grayscale(mut args: ArgumentResult, visitor: &mut Visitor) -> Sass
                 .into())
         }
     };
-    Ok(Value::Color(Box::new(color.desaturate(Number::one()))))
+    Ok(Value::Color(Arc::new(color.desaturate(Number::one()))))
 }
 
 pub(crate) fn complement(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -330,7 +330,7 @@ pub(crate) fn complement(mut args: ArgumentResult, visitor: &mut Visitor) -> Sas
     let color = args
         .get_err(0, "color")?
         .assert_color_with_name("color", args.span())?;
-    Ok(Value::Color(Box::new(color.complement())))
+    Ok(Value::Color(Arc::new(color.complement())))
 }
 
 pub(crate) fn invert(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -362,7 +362,7 @@ pub(crate) fn invert(mut args: ArgumentResult, visitor: &mut Visitor) -> SassRes
         }
     };
     match args.get_err(0, "color")? {
-        Value::Color(c) => Ok(Value::Color(Box::new(
+        Value::Color(c) => Ok(Value::Color(Arc::new(
             c.invert(weight.unwrap_or_else(Number::one)),
         ))),
         Value::Dimension(SassNumber {
diff --git a/grass_internal/src/builtin/functions/color/hwb.rs b/grass_internal/src/builtin/functions/color/hwb.rs
index cceb0ea..3144c88 100644
--- a/grass_internal/src/builtin/functions/color/hwb.rs
+++ b/grass_internal/src/builtin/functions/color/hwb.rs
@@ -78,7 +78,7 @@ fn hwb_inner(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Valu
         None => Number::one(),
     };
 
-    Ok(Value::Color(Box::new(Color::from_hwb(
+    Ok(Value::Color(Arc::new(Color::from_hwb(
         hue,
         whiteness.num,
         blackness.num,
diff --git a/grass_internal/src/builtin/functions/color/opacity.rs b/grass_internal/src/builtin/functions/color/opacity.rs
index 3fb384b..f4e9723 100644
--- a/grass_internal/src/builtin/functions/color/opacity.rs
+++ b/grass_internal/src/builtin/functions/color/opacity.rs
@@ -104,7 +104,7 @@ fn opacify(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value>
 
     let amount = bound!(args, "amount", amount.num, amount.unit(), 0, 1);
 
-    Ok(Value::Color(Box::new(color.fade_in(amount))))
+    Ok(Value::Color(Arc::new(color.fade_in(amount))))
 }
 
 fn transparentize(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult<Value> {
@@ -127,7 +127,7 @@ fn transparentize(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult
                 .into())
         }
     };
-    Ok(Value::Color(Box::new(color.fade_out(amount))))
+    Ok(Value::Color(Arc::new(color.fade_out(amount))))
 }
 
 pub(crate) fn declare(f: &mut GlobalFunctionMap) {
diff --git a/grass_internal/src/builtin/functions/color/other.rs b/grass_internal/src/builtin/functions/color/other.rs
index 76a73df..3f8351d 100644
--- a/grass_internal/src/builtin/functions/color/other.rs
+++ b/grass_internal/src/builtin/functions/color/other.rs
@@ -57,7 +57,7 @@ pub(crate) fn change_color(mut args: ArgumentResult, visitor: &mut Visitor) -> S
     opt_rgba!(args, blue, "blue", 0, 255);
 
     if red.is_some() || green.is_some() || blue.is_some() {
-        return Ok(Value::Color(Box::new(Color::from_rgba(
+        return Ok(Value::Color(Arc::new(Color::from_rgba(
             red.unwrap_or_else(|| color.red()),
             green.unwrap_or_else(|| color.green()),
             blue.unwrap_or_else(|| color.blue()),
@@ -84,7 +84,7 @@ pub(crate) fn change_color(mut args: ArgumentResult, visitor: &mut Visitor) -> S
     if hue.is_some() || saturation.is_some() || lightness.is_some() {
         // Color::as_hsla() returns more exact values than Color::hue(), etc.
         let (this_hue, this_saturation, this_lightness, this_alpha) = color.as_hsla();
-        return Ok(Value::Color(Box::new(Color::from_hsla(
+        return Ok(Value::Color(Arc::new(Color::from_hsla(
             hue.unwrap_or(this_hue),
             saturation.unwrap_or(this_saturation),
             lightness.unwrap_or(this_lightness),
@@ -93,9 +93,9 @@ pub(crate) fn change_color(mut args: ArgumentResult, visitor: &mut Visitor) -> S
     }
 
     Ok(Value::Color(if let Some(a) = alpha {
-        Box::new(color.with_alpha(a))
+        Arc::new(color.with_alpha(a))
     } else {
-        Box::new(color)
+        color
     }))
 }
 
@@ -110,7 +110,7 @@ pub(crate) fn adjust_color(mut args: ArgumentResult, visitor: &mut Visitor) -> S
     opt_rgba!(args, blue, "blue", -255, 255);
 
     if red.is_some() || green.is_some() || blue.is_some() {
-        return Ok(Value::Color(Box::new(Color::from_rgba(
+        return Ok(Value::Color(Arc::new(Color::from_rgba(
             color.red() + red.unwrap_or_else(Number::zero),
             color.green() + green.unwrap_or_else(Number::zero),
             color.blue() + blue.unwrap_or_else(Number::zero),
@@ -137,7 +137,7 @@ pub(crate) fn adjust_color(mut args: ArgumentResult, visitor: &mut Visitor) -> S
     if hue.is_some() || saturation.is_some() || lightness.is_some() {
         // Color::as_hsla() returns more exact values than Color::hue(), etc.
         let (this_hue, this_saturation, this_lightness, this_alpha) = color.as_hsla();
-        return Ok(Value::Color(Box::new(Color::from_hsla(
+        return Ok(Value::Color(Arc::new(Color::from_hsla(
             this_hue + hue.unwrap_or_else(Number::zero),
             this_saturation + saturation.unwrap_or_else(Number::zero),
             this_lightness + lightness.unwrap_or_else(Number::zero),
@@ -147,9 +147,9 @@ pub(crate) fn adjust_color(mut args: ArgumentResult, visitor: &mut Visitor) -> S
 
     Ok(Value::Color(if let Some(a) = alpha {
         let temp_alpha = color.alpha();
-        Box::new(color.with_alpha(temp_alpha + a))
+        Arc::new(color.with_alpha(temp_alpha + a))
     } else {
-        Box::new(color)
+        color
     }))
 }
 
@@ -198,7 +198,7 @@ pub(crate) fn scale_color(mut args: ArgumentResult, visitor: &mut Visitor) -> Sa
     let alpha = get_arg(&mut args, "alpha", -100.0, 100.0)?;
 
     if red.is_some() || green.is_some() || blue.is_some() {
-        return Ok(Value::Color(Box::new(Color::from_rgba(
+        return Ok(Value::Color(Arc::new(Color::from_rgba(
             scale(color.red(), red.unwrap_or_else(Number::zero), Number(255.0)),
             scale(
                 color.green(),
@@ -224,7 +224,7 @@ pub(crate) fn scale_color(mut args: ArgumentResult, visitor: &mut Visitor) -> Sa
     if saturation.is_some() || lightness.is_some() {
         // Color::as_hsla() returns more exact values than Color::hue(), etc.
         let (this_hue, this_saturation, this_lightness, this_alpha) = color.as_hsla();
-        return Ok(Value::Color(Box::new(Color::from_hsla(
+        return Ok(Value::Color(Arc::new(Color::from_hsla(
             scale(this_hue, Number::zero(), Number(360.0)),
             scale(
                 this_saturation,
@@ -252,7 +252,7 @@ pub(crate) fn scale_color(mut args: ArgumentResult, visitor: &mut Visitor) -> Sa
         let this_whiteness = color.whiteness() * Number(100.0);
         let this_blackness = color.blackness() * Number(100.0);
 
-        return Ok(Value::Color(Box::new(Color::from_hwb(
+        return Ok(Value::Color(Arc::new(Color::from_hwb(
             scale(this_hue, Number::zero(), Number(360.0)),
             scale(
                 this_whiteness,
@@ -274,9 +274,9 @@ pub(crate) fn scale_color(mut args: ArgumentResult, visitor: &mut Visitor) -> Sa
 
     Ok(Value::Color(if let Some(a) = alpha {
         let temp_alpha = color.alpha();
-        Box::new(color.with_alpha(scale(temp_alpha, a, Number::one())))
+        Arc::new(color.with_alpha(scale(temp_alpha, a, Number::one())))
     } else {
-        Box::new(color)
+        color
     }))
 }
 
diff --git a/grass_internal/src/builtin/functions/color/rgb.rs b/grass_internal/src/builtin/functions/color/rgb.rs
index 12ba5e2..d7a8e76 100644
--- a/grass_internal/src/builtin/functions/color/rgb.rs
+++ b/grass_internal/src/builtin/functions/color/rgb.rs
@@ -72,7 +72,7 @@ fn inner_rgb_2_arg(
 
     let color = color.assert_color_with_name("color", args.span())?;
     let alpha = alpha.assert_number_with_name("alpha", args.span())?;
-    Ok(Value::Color(Box::new(color.with_alpha(Number(
+    Ok(Value::Color(Arc::new(color.with_alpha(Number(
         percentage_or_unitless(&alpha, 1.0, "alpha", args.span(), visitor)?,
     )))))
 }
@@ -120,7 +120,7 @@ fn inner_rgb_3_arg(
     let green = green.assert_number_with_name("green", span)?;
     let blue = blue.assert_number_with_name("blue", span)?;
 
-    Ok(Value::Color(Box::new(Color::from_rgba_fn(
+    Ok(Value::Color(Arc::new(Color::from_rgba_fn(
         Number(fuzzy_round(percentage_or_unitless(
             &red, 255.0, "red", span, visitor,
         )?)),
@@ -432,7 +432,7 @@ pub(crate) fn mix(mut args: ArgumentResult, visitor: &mut Visitor) -> SassResult
                 .into())
         }
     };
-    Ok(Value::Color(Box::new(color1.mix(&color2, weight))))
+    Ok(Value::Color(Arc::new(color1.mix(&color2, weight))))
 }
 
 pub(crate) fn declare(f: &mut GlobalFunctionMap) {
diff --git a/grass_internal/src/builtin/mod.rs b/grass_internal/src/builtin/mod.rs
index 5017c9d..257bdd8 100644
--- a/grass_internal/src/builtin/mod.rs
+++ b/grass_internal/src/builtin/mod.rs
@@ -27,6 +27,7 @@ mod builtin_imports {
     };
 
     pub(crate) use std::{
+        sync::Arc,
         cmp::Ordering,
         collections::{BTreeMap, BTreeSet},
     };
diff --git a/grass_internal/src/color/mod.rs b/grass_internal/src/color/mod.rs
index 2afa55c..6d14ce7 100644
--- a/grass_internal/src/color/mod.rs
+++ b/grass_internal/src/color/mod.rs
@@ -197,7 +197,7 @@ impl Color {
     /// Mix two colors together with weight
     /// Algorithm adapted from
     /// <https://github.com/sass/dart-sass/blob/0d0270cb12a9ac5cce73a4d0785fecb00735feee/lib/src/functions/color.dart#L718>
-    pub fn mix(self, other: &Color, weight: Number) -> Self {
+    pub fn mix(&self, other: &Color, weight: Number) -> Self {
         let weight = weight.clamp(0.0, 100.0);
         let normalized_weight = weight * Number(2.0) - Number::one();
         let alpha_distance = self.alpha() - other.alpha();
@@ -445,21 +445,21 @@ impl Color {
     }
 
     /// Change `alpha` to value given
-    pub fn with_alpha(self, alpha: Number) -> Self {
+    pub fn with_alpha(&self, alpha: Number) -> Self {
         Color::from_rgba(self.red(), self.green(), self.blue(), alpha)
     }
 
     /// Makes a color more opaque.
     /// Takes a color and a number between 0 and 1,
     /// and returns a color with the opacity increased by that amount.
-    pub fn fade_in(self, amount: Number) -> Self {
+    pub fn fade_in(&self, amount: Number) -> Self {
         Color::from_rgba(self.red(), self.green(), self.blue(), self.alpha() + amount)
     }
 
     /// Makes a color more transparent.
     /// Takes a color and a number between 0 and 1,
     /// and returns a color with the opacity decreased by that amount.
-    pub fn fade_out(self, amount: Number) -> Self {
+    pub fn fade_out(&self, amount: Number) -> Self {
         Color::from_rgba(self.red(), self.green(), self.blue(), self.alpha() - amount)
     }
 }
diff --git a/grass_internal/src/evaluate/visitor.rs b/grass_internal/src/evaluate/visitor.rs
index 1883a7d..0b37b0c 100644
--- a/grass_internal/src/evaluate/visitor.rs
+++ b/grass_internal/src/evaluate/visitor.rs
@@ -2427,24 +2427,25 @@ impl<'a> Visitor<'a> {
                 rhs,
                 allows_slash,
                 span,
-            } => self.visit_bin_op(*lhs, op, *rhs, allows_slash, span)?,
+            } => self.visit_bin_op((*lhs).clone(), op, (*rhs).clone(), allows_slash, span)?,
             AstExpr::True => Value::True,
             AstExpr::False => Value::False,
             AstExpr::Calculation { name, args } => {
                 self.visit_calculation_expr(name, args, self.span_before)?
             }
             AstExpr::FunctionCall(func_call) => self.visit_function_call_expr(func_call)?,
-            AstExpr::If(if_expr) => self.visit_ternary(*if_expr)?,
+            AstExpr::If(if_expr) => self.visit_ternary((*if_expr).clone())?,
             AstExpr::InterpolatedFunction(func) => self.visit_interpolated_func_expr(func)?,
             AstExpr::Map(map) => self.visit_map(map)?,
             AstExpr::Null => Value::Null,
-            AstExpr::Paren(expr) => self.visit_expr(*expr)?,
+            AstExpr::Paren(expr) => self.visit_expr((*expr).clone())?,
             AstExpr::ParentSelector => self.visit_parent_selector(),
-            AstExpr::UnaryOp(op, expr, span) => self.visit_unary_op(op, *expr, span)?,
+            AstExpr::UnaryOp(op, expr, span) => self.visit_unary_op(op, (*expr).clone(), span)?,
             AstExpr::Variable { name, namespace } => self.env.get_var(name, namespace)?,
-            AstExpr::Supports(condition) => {
-                Value::String(self.visit_supports_condition(*condition)?, QuoteKind::None)
-            }
+            AstExpr::Supports(condition) => Value::String(
+                self.visit_supports_condition((*condition).clone())?,
+                QuoteKind::None,
+            ),
         })
     }
 
@@ -2459,7 +2460,8 @@ impl<'a> Visitor<'a> {
                 AstExpr::FunctionCall(FunctionCallExpr { ref name, .. })
                     if name.as_str().to_ascii_lowercase() == "var" =>
                 {
-                    let result = self.visit_calculation_value(*inner, in_min_or_max, span)?;
+                    let result =
+                        self.visit_calculation_value((*inner).clone(), in_min_or_max, span)?;
 
                     if let CalculationArg::String(text) = result {
                         CalculationArg::String(format!("({})", text))
@@ -2467,7 +2469,7 @@ impl<'a> Visitor<'a> {
                         result
                     }
                 }
-                _ => self.visit_calculation_value(*inner, in_min_or_max, span)?,
+                _ => self.visit_calculation_value((*inner).clone(), in_min_or_max, span)?,
             },
             AstExpr::String(string_expr, _span) => {
                 debug_assert!(string_expr.1 == QuoteKind::None);
@@ -2475,8 +2477,8 @@ impl<'a> Visitor<'a> {
             }
             AstExpr::BinaryOp { lhs, op, rhs, .. } => SassCalculation::operate_internal(
                 op,
-                self.visit_calculation_value(*lhs, in_min_or_max, span)?,
-                self.visit_calculation_value(*rhs, in_min_or_max, span)?,
+                self.visit_calculation_value((*lhs).clone(), in_min_or_max, span)?,
+                self.visit_calculation_value((*rhs).clone(), in_min_or_max, span)?,
                 in_min_or_max,
                 !self.flags.in_supports_declaration(),
                 self.options,
diff --git a/grass_internal/src/parse/stylesheet.rs b/grass_internal/src/parse/stylesheet.rs
index 2f5e1e4..5e20a77 100644
--- a/grass_internal/src/parse/stylesheet.rs
+++ b/grass_internal/src/parse/stylesheet.rs
@@ -3,7 +3,7 @@ use std::{
     collections::{BTreeMap, HashSet},
     ffi::OsString,
     mem,
-    path::{Path, PathBuf},
+    path::{Path, PathBuf}, sync::Arc,
 };
 
 use codemap::{CodeMap, Span, Spanned};
@@ -745,7 +745,7 @@ pub(crate) trait StylesheetParser<'a>: BaseParser<'a> + Sized {
                         }
 
                         buffer
-                            .add_expr(AstExpr::Supports(Box::new(query)).span(self.span_before()));
+                            .add_expr(AstExpr::Supports(Arc::new(query)).span(self.span_before()));
 
                         if !is_declaration {
                             buffer.add_char(')');
diff --git a/grass_internal/src/parse/value.rs b/grass_internal/src/parse/value.rs
index 23dbafe..0a230f0 100644
--- a/grass_internal/src/parse/value.rs
+++ b/grass_internal/src/parse/value.rs
@@ -1,4 +1,4 @@
-use std::{iter::Iterator, marker::PhantomData};
+use std::{iter::Iterator, marker::PhantomData, sync::Arc};
 
 use codemap::Spanned;
 
@@ -539,9 +539,9 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
         } else {
             self.single_expression = Some(
                 AstExpr::BinaryOp {
-                    lhs: Box::new(left.node),
+                    lhs: Arc::new(left.node),
                     op: operator,
-                    rhs: Box::new(right.node),
+                    rhs: Arc::new(right.node),
                     allows_slash: false,
                     span,
                 }
@@ -742,7 +742,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
             parser
                 .flags_mut()
                 .set(ContextFlags::IN_PARENS, was_in_parentheses);
-            return Ok(AstExpr::Paren(Box::new(first.node)).span(first.span));
+            return Ok(AstExpr::Paren(Arc::new(first.node)).span(first.span));
         }
 
         parser.whitespace()?;
@@ -842,7 +842,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
             })
         ) {
             let color = self.parse_hex_color_contents(parser)?;
-            return Ok(AstExpr::Color(Box::new(color)).span(parser.toks_mut().span_from(start)));
+            return Ok(AstExpr::Color(Arc::new(color)).span(parser.toks_mut().span_from(start)));
         }
 
         let after_hash = parser.toks().cursor();
@@ -851,7 +851,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
             parser.toks_mut().set_cursor(after_hash);
             let color = self.parse_hex_color_contents(parser)?;
             return Ok(
-                AstExpr::Color(Box::new(color)).span(parser.toks_mut().span_from(after_hash))
+                AstExpr::Color(Arc::new(color)).span(parser.toks_mut().span_from(after_hash))
             );
         }
 
@@ -940,7 +940,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
 
         let span = op_span.merge(parser.toks().current_span());
 
-        Ok(AstExpr::UnaryOp(operator, Box::new(operand.node), span).span(span))
+        Ok(AstExpr::UnaryOp(operator, Arc::new(operand.node), span).span(span))
     }
 
     fn expect_unary_operator(parser: &mut P) -> SassResult<UnaryOp> {
@@ -1159,7 +1159,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
             if plain == "if" && parser.toks().next_char_is('(') {
                 let call_args = parser.parse_argument_invocation(false, false)?;
                 let span = call_args.span;
-                return Ok(AstExpr::If(Box::new(Ternary(call_args))).span(span));
+                return Ok(AstExpr::If(Arc::new(Ternary(call_args))).span(span));
             } else if plain == "not" {
                 parser.whitespace()?;
 
@@ -1167,7 +1167,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
 
                 let span = parser.toks_mut().span_from(start);
 
-                return Ok(AstExpr::UnaryOp(UnaryOp::Not, Box::new(value.node), span).span(span));
+                return Ok(AstExpr::UnaryOp(UnaryOp::Not, Arc::new(value.node), span).span(span));
             }
 
             let lower_ref = lower.as_ref().unwrap();
@@ -1181,7 +1181,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
                 }
 
                 if let Some(color) = NAMED_COLORS.get_by_name(lower_ref.as_str()) {
-                    return Ok(AstExpr::Color(Box::new(Color::new(
+                    return Ok(AstExpr::Color(Arc::new(Color::new(
                         color[0],
                         color[1],
                         color[2],
@@ -1535,7 +1535,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
                 parser.whitespace()?;
                 parser.expect_char(')')?;
 
-                Ok(AstExpr::Paren(Box::new(value)).span(parser.toks_mut().span_from(start)))
+                Ok(AstExpr::Paren(Arc::new(value)).span(parser.toks_mut().span_from(start)))
             }
             _ if !parser.looking_at_identifier() => Err((
                 "Expected number, variable, function, or calculation.",
@@ -1567,7 +1567,7 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
                 if let Some(calc) = calculation {
                     Ok(calc)
                 } else if lowercase == "if" {
-                    Ok(AstExpr::If(Box::new(Ternary(
+                    Ok(AstExpr::If(Arc::new(Ternary(
                         parser.parse_argument_invocation(false, false)?,
                     )))
                     .span(parser.toks_mut().span_from(start)))
@@ -1601,13 +1601,13 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
                     let span = product.span.merge(rhs.span);
 
                     product.node = AstExpr::BinaryOp {
-                        lhs: Box::new(product.node),
+                        lhs: Arc::new(product.node),
                         op: if op == '*' {
                             BinaryOp::Mul
                         } else {
                             BinaryOp::Div
                         },
-                        rhs: Box::new(rhs.node),
+                        rhs: Arc::new(rhs.node),
                         allows_slash: false,
                         span,
                     };
@@ -1655,13 +1655,13 @@ impl<'a, 'c, P: StylesheetParser<'a>> ValueParser<'a, 'c, P> {
                     let span = sum.span.merge(rhs.span);
 
                     sum = AstExpr::BinaryOp {
-                        lhs: Box::new(sum.node),
+                        lhs: Arc::new(sum.node),
                         op: if next == '+' {
                             BinaryOp::Plus
                         } else {
                             BinaryOp::Minus
                         },
-                        rhs: Box::new(rhs.node),
+                        rhs: Arc::new(rhs.node),
                         allows_slash: false,
                         span,
                     }
diff --git a/grass_internal/src/value/mod.rs b/grass_internal/src/value/mod.rs
index 1177e11..6de38bc 100644
--- a/grass_internal/src/value/mod.rs
+++ b/grass_internal/src/value/mod.rs
@@ -1,4 +1,4 @@
-use std::cmp::Ordering;
+use std::{cmp::Ordering, sync::Arc};
 
 use codemap::{Span, Spanned};
 
@@ -35,7 +35,7 @@ pub(crate) enum Value {
     Null,
     Dimension(SassNumber),
     List(Vec<Value>, ListSeparator, Brackets),
-    Color(Box<Color>),
+    Color(Arc<Color>),
     String(String, QuoteKind),
     Map(SassMap),
     ArgList(ArgList),
@@ -155,9 +155,9 @@ impl Value {
         }
     }
 
-    pub fn assert_color_with_name(self, name: &str, span: Span) -> SassResult<Color> {
+    pub fn assert_color_with_name(self, name: &str, span: Span) -> SassResult<Arc<Color>> {
         match self {
-            Value::Color(c) => Ok(*c),
+            Value::Color(c) => Ok(c),
             _ => Err((
                 format!(
                     "${name}: {} is not a color.",